Zero or more
strings
that are themselves each zero or more characters, each
optionally with leading and/or trailing
space characters,
and each separated from the next by a single
","
(comma) character. Each string itself
must
not begin or end with any
space characters,
and each string itself
must
not contain any
","
(comma) characters.

A
valid hash-name reference to an element of type
type
is a string that starts with a
"#"
character, followed by a string which
exactly matches the value of the
name
attribute of an element of type
type
anywhere in the document.

A comma-separated list of at
least six
integers, with the
total number of integers in the list being even (that is,
six or eight or ten numbers, and so on). Each pair of
integers represents a coordinate, in CSS pixels, given as
the distances from, respectively, the left and the top of
the image; all the coordinates together represent the
points of the polygon, in order.